Adds a Flow Completed span carrying flow_name, duration_ms and outcome,
emitted when a flow finishes or fails. Elapsed time comes from a monotonic
stamp taken at flow start and cleared on use.
Kept separate from the Flow Execution span rather than holding that one open:
it is emitted and closed at start and the daily aggregate counts it, so
holding it would drop every run that is killed or crashes from the execution
count. A killed run now simply has no Flow Completed row, and the count is
unaffected.
Elapsed time is an explicit duration_ms attribute rather than the span's own
duration, which the ingestion pipeline stores as a suffixed string
("0.0000184s") that downstream aggregation parses to zero.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ASfWmW3RGy4qAQm6s8U9jH
fbe1debd96